Question

The demand for subassembly S is 110 units in week 7. Each unit of S requires 2 units of T and 2 units of U. Each unit of T requires 2 units of V, 2 units of W, and 2 units of X. Finally, each unit of U requires 1 unit of Y and 3 units of Z. One firm manufactures all items. It takes 2 weeks to make S, 1 week to make T, 2 weeks make U, 2 weeks to make V, 3 weeks to make W, 1 week to make X, 2 weeks to make Y, and 1 week to make Z.

Suppose that in addition to 110 units of S, there is also a demand for 30 units of U, which is a component of S. The 30 units of U are needed for maintenance purposes. These units are needed in week 6. Modify the net material requirements plan to reflect change.

Construct a new net material requirements plan

Answer 1

Formulas:

Gross requirement of the child item = Planned order release quantity of the parent item as per BOM requirement

Net requirement = Gross Requirement of week – projected on-hand of previous week – Scheduled Receipts of week

Projected on-hand (POH) = Projected on-hand of previous week + Scheduled Receipt of week – Gross Requirement of week + Planned order receipt (PORc) of week

Planned order receipt = if the project-on-hand is negative, place an order.

the New MRP schedule is as follows:

Period		1	2	3	4	5	6	7
Item S	Gross requirements							110
OH = 0	Scheduled receipts							0
LT = 2	Projected available balance							0
SS = 0	Net requirements							1100
Q = L4L	Planned order receipts							110
	Planned order releases					110
Period	(2 units for S)	1	2	3	4	5	6	7
Item T	Gross requirements					220
OH = 0	Scheduled receipts					0
LT = 1	Projected available balance					0
SS = 0	Net requirements					220
Q = L4L	Planned order receipts					220
	Planned order releases				220
Period	(2 units for S)	1	2	3	4	5	6	7
Item U	Gross requirements					220	30
OH = 0	Scheduled receipts					0	0
LT = 2	Projected available balance					0	0
SS = 0	Net requirements					220	30
Q = L4L	Planned order receipts					220	30
	Planned order releases			220	30
Period	2 units for T	1	2	3	4	5	6	7
Item V	Gross requirements	0	0	0	440
OH = 0	Scheduled receipts				0
LT = 2	Projected available balance				0
SS = 0	Net requirements				440
Q = L4L	Planned order receipts				440
	Planned order releases		440
Period	2 units for T	1	2	3	4	5	6	7
Item W	Gross requirements	0	0	0	440	0
OH = 0	Scheduled receipts				0
LT = 3	Projected available balance				0
SS = 0	Net requirements				440
Q = L4L	Planned order receipts				440
	Planned order releases	440
Period	2 unit for T	1	2	3	4	5	6	7
Item X	Gross requirements	0	0	0	440	0
OH = 0	Scheduled receipts				0
LT = 1	Projected available balance				0
SS = 0	Net requirements				440
Q = L4L	Planned order receipts				440
	Planned order releases			440
Period	1 unit for U	1	2	3	4	5	6	7
Item Y	Gross requirements	0	0	220	30	0	0	0
OH = 0	Scheduled receipts			0	0
LT = 2	Projected available balance			0	0
SS = 0	Net requirements			220	30
Q = L4L	Planned order receipts			220	30
	Planned order releases	220	30
Period	3 unit for U	1	2	3	4	5	6	7
Item Z	Gross requirements	0	0	660	90	0	0	0
OH = 0	Scheduled receipts			0	0
LT = 1	Projected available balance			0	0
SS = 0	Net requirements			660	90
Q = L4L	Planned order receipts			660	90
	Planned order releases		660	90